The invention relates to a combustion diagnosis system for a combustion chamber of a combustion system, comprising a diagnostic element which can be inserted into a combustion chamber wall, communicates with the combustion chamber and is penetrated by a light guide, by means of which electromagnetic radiation occurring in the combustion chamber can be detected.
Such a combustion diagnosis system is known from the state of the art. With this combustion diagnosis system, a light guide is guided centrally through an ignition plug in order to detect electromagnetic radiation in the combustion chamber.
It has, however, been shown that the electromagnetic radiation detected does not provide a complete picture of the combustion occurring in the combustion chamber.
The object underlying the invention is therefore to improve a combustion diagnosis system of the generic type in such a manner that the course of combustion in the combustion chamber can be detected even better.
This object is accomplished in accordance with the invention, in a combustion diagnosis system of the type described at the outset, in that the diagnostic element is penetrated by several light guides and that with each of the several light guides the electromagnetic radiation from a spatial segment of the combustion chamber associated with this light guide is detectable and that the spatial segments are different respective segments of the combustion chamber.
The advantage of the inventive solution is to be seen in the fact that as a result it is possible, due to the use of a plurality of light guides and due to the allocation of different spatial segments to the individual light guides, to analyze the combustion occurring in the combustion chamber in spatial resolution and thus to detect the propagation of the combustion in the combustion chamber considerably better. The spatial propagation of combustion in the combustion chamber may, for example, be analyzed advantageously as a result.
In principle, it would be conceivable to dimension and arrange the spatial segments such that these overlap one another so that the electromagnetic radiation detected in the individual light guides could originate, at least partially, from the same combustion process.
However, in order to obtain a clear, spatial resolution it is preferably provided for the spatial segments of the combustion chamber to be arranged therein so as not to overlap, i.e. the electromagnetic radiation from one spatial segment is detected only by one light guide and the other light guides cannot detect this electromagnetic radiation.
The position of the spatial segments may, in principle, be selected in any optional manner. It is particularly favorable when the spatial segments of the combustion chamber are arranged around a central axis so that the development of the combustion around this central axis can be analyzed advantageously in spatial resolution.
A particularly favorable solution provides for the central axis to represent a central axis of the diagnostic element so that the spatial segments are in a position to cover areas of the combustion chamber located around this central axis.
In the case of an ignition plug designed as diagnostic element, it is preferably provided for the ignition spark generated by this to be located close to the central axis, preferably approximately concentric to it, so that the combustion originating from the ignition spark can be analyzed advantageously.
In addition, in the case of an injection nozzle designed as diagnostic element it is preferably provided for the injection channel to be located close to the central axis, preferably approximately concentric to this, so that the combustion forming around the injected fuel can likewise be analyzed advantageously due to the individual spatial segments.
In this respect, it is particularly favorable when the spatial segments are arranged symmetrically around the central axis so that with the sum of the spatial segments it is possible to analyze a considerable area of the combustion chamber around the central axis in spatial resolution.
It is particularly favorable when the sum of all the spatial segments covers a subsection of the combustion chamber extending around the central axis to a considerable proportion so that it is possible to follow the propagation of the combustion and the resulting electromagnetic radiation connected thereto in the direction of all the radial directions relative to the central axis in spatial resolution.
With respect to the arrangement of the light guides themselves, no further details have so far been given.
One advantageous embodiment, for example, provides for the light guides to be arranged in a passage in a member of the diagnostic element.
It is particularly favorable when one light-guide end of the light guides is located in the passage in front of an opening thereof facing the combustion chamber. The advantage of this solution is to be seen in the fact that with it the light-guide end is arranged so as to be protected in the passage in relation to the combustion chamber.
In this respect it is particularly advantageous when a section of the passage located between the light-guide end and the opening of the passage facing the combustion chamber forms an aperture stop for the electromagnetic radiation entering the light guide.
In order to obtain as large an aperture as possible, it is preferably provided for the cross section of this section to be designed to broaden from the light-guide end as far as the opening of the passage facing the combustion chamber.
In principle, it is conceivable within the scope of the inventive solution to provide the diagnostic element as a separate element, wherein in this case the combustion chamber wall must have an opening for the insertion of the diagnostic element. In this respect, the diagnostic element can preferably be fixed detachably on the combustion chamber wall, for example, be screwed into a threaded opening of the combustion chamber wall.
However, a particularly favorable solution provides for a functionally necessary element of the combustion system to be designed as diagnostic element, i.e. for an element necessary in any case for the functioning of the combustion system, such as, for example, an ignition plug or a spark plug or an injection nozzle, to be designed in addition as diagnostic element.
With respect to the evaluation of the electromagnetic radiations coming from the individual spatial segments, no further details have so far been given. One advantageous embodiment provides for the light guides to be connected to a diagnosis generating unit, preferably guided to it.
Such a diagnosis generating unit could be designed, for example, such that it detects and evaluates the electromagnetic radiation in the individual light guides serially.
It is, however, particularly favorable when each light guide is guided to its own detection unit, wherein this solution is advantageous on account of its constructional simplicity which makes it unnecessary to connect a single detection unit to each individual light guide.
In addition, a further development of this solution is advantageous to the effect that it is possible to detect the electromagnetic radiation in all the light guides simultaneously by means of respective detection units.
The inventive diagnostic system is particularly advantageous when the detection unit detects the electromagnetic radiation in spectral resolution so that it is possible to detect the intensity of individual spectral components.
In this respect, it would be conceivable, in principle, to detect one spectral component with regard to its intensity for each detection unit. Since, however, absolute measurements of the intensity are difficult to evaluate to obtain results concerning an optimum combustion it is preferably provided for the detection unit to detect several spectral components of the electromagnetic radiation so that it is possible to put the intensity of the individual spectral components in relation to one another.
With respect to the evaluation of the intensities detected by the detection units, it is preferably provided for all the detection units to be coupled to a common evaluation unit which then detects the intensities in the individual detection units and puts these in relation to one another on account of the spatial resolution in order to provide a diagnosis of the combustion taking place in the combustion chamber.
In order to detect the combustion processes as extensively as possible it is preferably provided for the diagnostic element to be provided, in addition, with a pressure sensor detecting the pressure in the combustion chamber. Such a pressure sensor enables the state of the combustion to be detected in addition and thus the electromagnetic radiation to be placed in relation to the state of the combustion and evaluated.
A further, advantageous solution provides for the evaluation unit to be coupled to the pressure sensor in order to place the measured pressure in relation to the spatial resolution of the electromagnetic radiation.
Furthermore, it is preferably provided for the evaluation unit to detect, in addition, a mechanical state of the combustion system, in the case of a piston engine the mechanical position of the piston, via a separate sensor.
Additional features and advantages of the inventive solution are the subject matter of the following description as well as the drawings illustrating several embodiments.